title: Comparisons among Tuli-, Brahman-, and Angus-sired heifers: intake, digesta kinetics, and grazing behavior.
abstract: As part of an evaluation of Tuli crossbred cattle, forage intake, digesta kinetics, and grazing behavior were estimated in two Texas environments. In humid east Texas, Tuli x Brahman heifers were compared with purebred Angus and Brahman and Angus x Brahman heifers. Fecal output, forage intake, compartmental mass, and compartmental residence time did not differ among breeds. Angus and Brahman heifers had different (P < . 02) gastrointestinal residence times (51.1+/-1.56 vs 43.1+/-1.56 h, respectively), but values for the purebreds did not differ from those for Tuli x Brahman or Angus x Brahman heifers. Angus heifers had shorter (P < .05) 24-h grazing times (398+/-15.4 min/d) and fewer (P < .05) grazing periods (7+/-.4) than Tuli x Brahman (552+/-16.8 min/d and 10+/-.4), Angus x Brahman (507+/-18.4 min/d and 9+/-.5), and Brahman (560-/+ 16.8 min/d and 9+/-.4, respectively) heifers. In semiarid southwest Texas, Tuli x Angus heifers were compared with purebred Angus and Brahman and Brahman x Angus heifers. Fecal output and forage intake were similar in Tuli x Angus and Brahman x Angus heifers (14.2+/-.69 and 14.9+/-.91 g fecal DM/ [d.kg BW] and 24.5+/-1.33 and 25.6+/-1.75 g/d of forage DMI, respectively) but higher (P < .05) than those of purebred Brahman heifers (12.2+/-.64 and 20.3+/-1.23 g/[d.kg BW] of fecal DM and forage DMI, respectively). Grazing times did not differ among breeds. We conclude that Tuli-sired heifers are likely to be as productive as Brahman crossbred heifers in Texas, based on the similarities in intake, digesta dynamics, and grazing behavior.
authors.affiliation: Texas Agricultural Experiment Station, Texas A&M University System, Uvalde 78801-6205, USA.
authors.forename: T D
authors.initials: TD
authors.lastname: Forbes
authors.forename: F M
authors.initials: FM
authors.lastname: Rouquette
authors.forename: J W
authors.initials: JW
authors.lastname: Holloway
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D001947:Breeding; D002417:Cattle / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004063:Digestion / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D005243:Feces; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D013997:Time Factors